122 PLANT DISEASES 



Dead and diseased seedlings should be removed and 

 burned. 



Hartig, Unters. aus dem Forstbot. Inst., vol. i. p. i. 

 Hartig and Somerville, Diseases of Trees, p. 78, figs. 



Rosellinia ligniaria, Nitschke. — This fungus has been 

 observed by Mr. W. Carruthers, F.R.S., to attack hving 

 ash-trees, eventually causing death. Specimens were 

 exhibited at the Linnean Society's meeting, December 16, 

 1897. 



GUMMOSIS OF ACACIA 



{Pleospora gummipara, Oud. 

 = Coryneum gummiparum, Oud.) 



Oudemans states that the production of Arabian and 

 Senegal gum is due to the presence of this fungous para- 

 site on species of Acacia. 



Oudemans, Hedwigia, 1883, pp. 131 and 161. 



HYPOCREACEAE 



Ergot 

 {Claviceps purpurea, Tul.) 



This well-known disease is often abundantly developed 

 in the ears of various cereals, especially rye ; it also 

 attacks various pasture grasses. 



Inoculation takes place when the plants are in bloom, 

 the mycelium developing in the ovary, replacing the seed. 



